Buzzing over pa when laptop power lead is plugged in [Archive]

Jays karaoke

12-03-2010, 05:17 PM

Hi, I'm after some advice for a friend as I have never come across this.

When The power supply for the laptop is plugged in he get's a very annoying buzzing sound over the speakers, but when he takes out the power lead it stops. can you guys suggest what he do please to eliminate this as i am stuck.

Thanks

Jay

rob1963

12-03-2010, 05:21 PM

A ground loop isolator should do the trick.

Jays karaoke

12-03-2010, 05:25 PM

thanks Rob

Excalibur

12-03-2010, 05:26 PM

The learned Mr James is correct in his suggestion.

rob1963

12-03-2010, 05:29 PM

thanks Rob

No problem Jay.

They're only a few quid.

The learned Mr James is correct in his suggestion.

I think that's the first time I've been described as learned by a forum member...so I'm going to enjoy the moment.

Thanks Peter!

:beer1:

sweetie

12-03-2010, 05:49 PM

they are only a fiver on www.disco-world.co.uk

Alchemy

12-03-2010, 06:03 PM

Spot on Rob, I had exactly the same problem and this http://cgi.ebay.co.uk/GROUND-LOOP-ISOLATOR-GOLD-RCA-STOPS-BUZZING-201-086_W0QQitemZ390102477564QQcmdZViewItemQQptZUK_Com puting_CablesConnectors_RL?hash=item5ad3eb6afc
solved the problem.

notroubleclubber

12-03-2010, 07:30 PM

Ive used the above one when recording mixes live to another pc and it stopped it. Havent tried it in a live situation yet but cant see there being any probs.

8x18

12-03-2010, 08:26 PM

* Content Removed *

Excalibur

12-03-2010, 08:34 PM

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Aaaaaaaaaarrrrgggghhh you can't say that!. :bang: :bang: Yes it works, no it's probably not unsafe, cos the gear's probably double insulated, but earth cables are safety items, and you can't suggest removing them.

Corabar Entertainment

12-03-2010, 08:45 PM

MDD ---> instructing ---> advising ---> promoting best practice.....

.... for YEARS now!

.... and then you get something like THIS posted on here!
* Content Removed *:bang: :bang: :bang:

Excalibur

12-03-2010, 08:48 PM

MDD ---> instructing ---> advising ---> promoting best practice.....

.... for YEARS now!

.... and then you get something like THIS posted on here!:bang: :bang: :bang:

Why do you think I was so quick to back Rob up, and praise him? I hoped it might forestall the " Nigel solution". ;) ;)

Penfold42

12-03-2010, 08:54 PM

OMG have we really gone that low.....:(

Corabar Entertainment

12-03-2010, 08:56 PM

for once, this was a techie question that even I knew the answer to! :eek: :D :D :D

Penfold42

12-03-2010, 08:59 PM

for once, this was a techie question that even I knew the answer to! :eek: :D :D :D

I've also edited post's to reflect what was said.........didn't want anyone to try it. :)

Back on topic please. :)

A1DL

12-03-2010, 08:59 PM

To reiterate Peter's point, DO NOT remove the earth from any plugtop. If you do, the results could be serious or fatal. You will also most likely invalidate your PLI cover.

Ground loop interference is easily cured by running the DJ through a pair of DIs with a lift on pin 1 - alternatively you can get XLR inline adapters that do the same job a lot cheaper than a pair of AR133s.

Running the stage/DJ feeds off the same leg as the FOH desk & racks normally avoids the problem anyway. I can't remember the last time I had to ground lift a DJ.

Penfold42

12-03-2010, 09:01 PM

Excalibur

12-03-2010, 09:14 PM

OMG have we really gone that low.....:(
Praising Rob? It appears so. Sorry. :o :o :o

for once, this was a techie question that even I knew the answer to! :eek: :D :D :D
Don't sell yourself short. Lately your technical knowledge has been impeccable, even Tony A1 has been impressed by it. ;) ;)

I've also edited post's to reflect what was said.........didn't want anyone to try it. :)

Back on topic please. :)
You'rer being awfully serious and efficient lately. Are you feeling alright? :confused:

To reiterate Peter's point, DO NOT remove the earth from any plugtop. If you do, the results could be serious or fatal. You will also most likely invalidate your PLI cover.

Ground loop interference is easily cured by running the DJ through a pair of DIs with a lift on pin 1 - alternatively you can get XLR inline adapters that do the same job a lot cheaper than a pair of AR133s.

Running the stage/DJ feeds off the same leg as the FOH desk & racks normally avoids the problem anyway. I can't remember the last time I had to ground lift a DJ.

Clears throat. " Oo er Missus". :D :D :D :D

Corabar Entertainment

12-03-2010, 09:21 PM

Don't sell yourself short. Lately your technical knowledge has been impeccable, even Tony A1 has been impressed by it. ;) ;) :Laugh::Laugh::Laugh::Laugh::Laugh::Laugh:
:rofl::rofl::rofl::rofl::rofl::rofl::rofl:

rob1963

12-03-2010, 10:42 PM

Now listen to the voice of reason.

The voice of reason was in the first reply to this thread.

;)

discomobiledj

13-03-2010, 12:41 AM

Nigel's back then!

Corabar Steve

13-03-2010, 01:24 AM

The voice of reason was in the first reply to this thread.

;)
Has somebody deleted Shaun's post then? All I see is a post by you :sj:

Rowleys

13-03-2010, 06:37 AM

back to the topic..

I have has this very same problem for ages now and can say its doing my head in.

I have 2 ground loopers as i use a 5.1 usb sound card and use 2 channels out so i use two loopers.

This still does not fix the problem.

I used to be able to connect a external monitor and it would stop but now that's stopped working .

Please help

Excalibur

13-03-2010, 07:08 AM

The voice of reason was in the first reply to this thread.

;)
Don't milk it pal, I'm not going to praise you twice in one thread. ;) :D

back to the topic..

I have has this very same problem for ages now and can say its doing my head in.

I have 2 ground loopers as i use a 5.1 usb sound card and use 2 channels out so i use two loopers.

This still does not fix the problem.

I used to be able to connect a external monitor and it would stop but now that's stopped working .

Please help

Try a different power supply. Sometimes helps.

CRAZY K

13-03-2010, 07:20 PM

Don't milk it pal, I'm not going to praise you twice in one thread. ;) :D

Try a different power supply. Sometimes helps.

Wise advice, electricity is a strange thing--I worked at an Xmas Party in an ancient Village Hall recently which appeared to have some "intereference" on the mains circuit which caused intermttent noise over the radio mike---never had the problem before---never had it since:bang:

Far as I know there wasnt a beer cooler on the same circuit ;)

More recently, in my kitchen I have an extension lead with a 4 gang block.

I use it for running my laptop, Hi fi amp/speaker, a reading light etc, for some UNKNOWN reason if I plug in a sound to light unit/ chaser and plug in my floodlights the floods dont work--if i plug it into other single plugs in the kitchen it works fine--very strange thing electricity:confused:

Rowleys

14-03-2010, 07:39 AM

well a little update with new power pack the noise is well controlled but still there just a little bit in the bass

but I'm happy with that as it was really bad

Alchemy

14-03-2010, 10:29 AM

This problem only happens with cheap, mass produced switched mode power supplies. They automatically switch between 100v and 240v so only one adapter is required wherever the laptop is sold in the world. The safest alternative solution to the ground loop isolator is to source a fixed 240v power supply with the correct DC power output (You could try this Rowley).

Removing the earth obviously does isolate the RF noise and if the adapter is in good condition it offers a very minimal risk (don’t attack it with a screwdriver). However, as has been pointed out in earlier posts it is amateur solution to an issue that can be easily and cheaply solved with a ground loop isolator.

Rowleys

14-03-2010, 10:39 AM

like i have said ground loop does not work on this noise we are getting.

i have no idea but I'm looking to move from laptop to a PC system and not use a laptop

Alchemy

14-03-2010, 01:24 PM

like i have said ground loop does not work on this noise we are getting.

i have no idea but I'm looking to move from laptop to a PC system and not use a laptop

What I suggested was to buy a fixed voltage power supply (240v) with the same power output as your switched mode power supply. This should completely cure the noise (and you won't need the GLI).

sleah

14-03-2010, 01:55 PM

If after adding GLIs there is still hum, then look elsewhere. It may be a GLI is need elsewhere in the signal path, such as between the mixer and amp.
It may be worth moving the GLI around as well as adding additional ones.
Also check where there is an earth that it is good.
Chasing hum in a signal path can be a right :Censored:!

Alchemy

14-03-2010, 02:17 PM

Told you you should have read the topic Charlie :D :D :D

Gavin Matthews

14-03-2010, 02:35 PM

Oh my god I knew this forum was blue for a reason lol

MFEntertainment

10-12-2011, 07:57 AM

Hi guys,

I'm having this same problem with a new Samsung laptop. Can anybody suggest a good store to purchase a DC power supply from?

Model is Samsung SF310 in case it helps!

Also wondering where in a system you would put the Ground loop isolator?

Cheers

Alchemy

10-12-2011, 08:14 AM

A ground loop isolator will, almost certainly solve the problem, you pug it between the output of the sound card and the input of your mixer.

MFEntertainment

10-12-2011, 10:00 AM

Ah right - I'll get on the case and place an order then!

Let you know how I go!

Matt

Excalibur

10-12-2011, 10:35 AM

A ground loop isolator will, almost certainly solve the problem, you pug it between the output of the sound card and the input of your mixer.

Ah right - I'll get on the case and place an order then!

Let you know how I go!

Matt

Matt, you may want two isolators. If you run a two channel soundcard, you need one GLI per stereo channel. My rig with a DJ IO soundcard is wired permanently with two of the little blighters. I got the ones from CPC, which can be fastened down with screws or cable ties.

ultrasound disco

21-12-2011, 08:28 PM

I have found that some of the cheaper isolators are prone to hum interference if placed too close to say..a power lead :(

Kernow

21-12-2011, 09:34 PM

A ground loop isolator will, almost certainly solve the problem, you pug it between the output of the sound card and the input of your mixer.

And that helps :confused:
;) :D

JSideFx

14-11-2012, 03:57 PM

Sorry to bring up old problems but last week I bought myself a new laptop for djing, Only thing now is its buzzing through my speakers!, I have one of the mentioned isolators and it does the trick but now I have to make the decision do I keep using my new machine with the loop isolator and hope for the best or do I take the laptop back and change it? Ive already spoke to the people at pc world and they understand and are happy to swap it over for another.

Heres the new laptop I bought
http://www.pcworld.co.uk/gbuk/samsung-series-3-np355v5c-15-6-laptop-silver-17056502-pdt.html

I even made a small vid showing the fault to show them at pc world if I go down that route
Thanks

Pe7e

14-11-2012, 05:14 PM

It's not your laptop, it's the charger, you will almost certainly find if you disconnect it the buzz will disappear

JSideFx

14-11-2012, 05:18 PM

It's not your laptop, it's the charger, you will almost certainly find if you disconnect it the buzz will disappear

Yes thats true, Running on battery the buzzing stops

Excalibur

14-11-2012, 05:40 PM

Yes thats true, Running on battery the buzzing stops

Neither the laptop, nor the charger have a fault as such. It's a pain in the bottom that the hum appears, but not a sign of anything faulty. You may swap it for half the laptops in PC world before you find one that doesn't hum. One GLI per stereo channel is the simplest solution.

JSideFx

14-11-2012, 06:30 PM

DJ Jules

14-11-2012, 07:10 PM

My main worry is how reliable is using a GLI? Just feel when given the chance to change it might be the best option but I know what you're saying you never know which one is going to do it until you try it out

100% reliable. It's not filtering out the hum, it's electrically isolating the power supplies between your amp/speakers and the laptop. There is absolutely nothing wrong with your laptop and there is no point in changing it over.

Just to point out that even if you find a laptop which doesn't suffer from this problem, if you the power supply fails and you have to change it for a generic replacement at any point in the future - you might find you get the problem then anyway.

Julian

Excalibur

14-11-2012, 08:13 PM

100% reliable.
With one proviso. If you let them roll around on your deckstand, at some point, the fly leads will get pulled, and you'll get an intermittent loss of one or both channels. You then end up frantically wiggling them until you find a point at which they work, and try not to move anything at all. This way lies madness. Believe me.

The foolproof way is to lash the blighters to something. These kiddies (http://cpc.farnell.com/unbranded/a-1095/ground-loop-isolator/dp/AV12774) are easy to attach with screws or cable ties. Then fasten the cables down so they can't move, and attach fly leads to them. There are many ways of doing this, and I'm not going to list them all. Simply make sure that the cables from the GLI cannot move at all, because if you don't, you'll have problems.

Remember also that if you have a twin stereo channel sound card ( DJIO, Maya et al ) you will need two GLIs.

DazzyD

14-11-2012, 10:22 PM

With one proviso. If you let them roll around on your deckstand, at some point, the fly leads will get pulled, and you'll get an intermittent loss of one or both channels. You then end up frantically wiggling them until you find a point at which they work, and try not to move anything at all. This way lies madness. Believe me.

The foolproof way is to lash the blighters to something. These kiddies (http://cpc.farnell.com/unbranded/a-1095/ground-loop-isolator/dp/AV12774) are easy to attach with screws or cable ties. Then fasten the cables down so they can't move, and attach fly leads to them. There are many ways of doing this, and I'm not going to list them all. Simply make sure that the cables from the GLI cannot move at all, because if you don't, you'll have problems.

Remember also that if you have a twin stereo channel sound card ( DJIO, Maya et al ) you will need two GLIs.

I use an external USB SoundBlaster soundcard and it appears to have GLI built in as there is no humming through the speakers when using it. When I don't use it, I then utilise two GLIs as Peter has already mentioned.

JSideFx

17-11-2012, 02:45 AM

DJ Jules

17-11-2012, 07:27 AM

I was in asda today and bought one of these for £20 which solves the buzzing totally!, Worked great tonight and hopefully tomorrow
http://direct.asda.com/Trust-17260-70W-Notebook-Power-Adapter/000544901,default,pd.html

I don't want to rain on your parade, but every link I've found so far (http://www.ultrabook-accessories.co.uk/90w-samsung-np355v-np355v5c-laptop-ac-power-adapter-with-cord-p-60413.html) to replacement power supplies for your laptop say it should be rated at 90w - the one you bought is only rated at 70w, so it's underpowered and could overheat/fail.

Check the rating on the official power supply you've got and if it says 90w, then I'm afraid you shouldn't be using the Trust one. The good news is you can pick up 19v/90w laptop power supplies for peanuts on eBay (less than a tenner), the bad news is you've no idea if they'll solve your hum problem until you get them :(

Personally I would would stick with taking GLI's everywhere with me (including walk up gigs because I find my laptop's are Ok with some mixer/amp combinations but not others depending if they have built in ground lift or specific earth arrangements, etc).

Julian

Excalibur

17-11-2012, 08:28 AM

I don't want to rain on your parade, but every link I've found so far (http://www.ultrabook-accessories.co.uk/90w-samsung-np355v-np355v5c-laptop-ac-power-adapter-with-cord-p-60413.html) to replacement power supplies for your laptop say it should be rated at 90w - the one you bought is only rated at 70w, so it's underpowered and could overheat/fail.

I hadn't spotted that Julian, well done. My initial cursory search agrees with you.

katman

17-11-2012, 10:35 AM

I was in asda today and bought one of these for £20 which solves the buzzing totally!, Worked great tonight and hopefully tomorrow
http://direct.asda.com/Trust-17260-70W-Notebook-Power-Adapter/000544901,default,pd.html

The reason the buzzing has stopped is because that power supply only has a 2 core mains lead so it not earthed and cant cause an earth loop. Most modern laptop supplies have 3 core mains leads which is where the earthloop is created.

You may find that although that unit will RUN your laptop it will run quite hot as it is underated for your laptop and you may also find that the laptop doesnt charge when using that one.

Many modern laptops have electronic sensing of the power supply connected and adjust their charging based on the unit they detect. My Dell uses a third pin in the DC power lead for this puropse. An aftermarket Car power supply that I bought will power the laptop no problem at all but will NOT charge it because it lacks the communication neccessary.

You have also paid several times more for that power adapter than you would have paid for a ground loop isolator. You really should invest in one because although you dont have a ground loop now, you could easily suffer the problem again just by connecting something like a mains powered external hard drive to your machine.

JSideFx

17-11-2012, 11:27 AM

Thanks I have now got a GLI it arrived in the post today, That new power supply worked great last night and wasn't warm at all, The one for my old acer got really warm when using it but this new one seemed fine but thanks for the advice I can return it and I will look for a 90w one :(

Also on the bottom of the laptop it says: input 19v 3.16a (60W)

DJ Jules

19-11-2012, 06:36 AM

Also on the bottom of the laptop it says: input 19v 3.16a (60W)

If that's the case then the one you've got will do absolutely fine.

The one for my old acer got really warm when using it but this new one seemed fine but thanks for the advice I can return it and I will look for a 90w one :(

No need, 60w is less than the 70w rated capacity so you'll be fine. Stick with what you've got :) If the laptop is rated at 60w, I don't know why all of the replacements are rated at 90w. It might be something to do with accessories (i.e. if you added a port replicator and/or docking station it might require 90w, but the laptop alone only needs 60w).

Julian